SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85fb803af8d7162594a1e1e437f0d2ca2eb53941b4f4c8e4a8aae38f0bde6260' 
  AND token = 'gremKeGB+T3Vh1EzswKzyIXDBIUkgn3u9cNYUQR/LRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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