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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e5f26b1c1e0e7cb3d368dbf3989de9b59fcb2ce9ffe10e6382c5142a47df67' 
  AND token = 'GkgQXmeTBT8np+u9B1qgq/QS6g1bCY2vyrPArv+M6s4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}