SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce4037b75a189e61856b0c0830292e6cfbe27af3cbcdaccfc850d760d8493cab' 
  AND token = 'pyj3p+/Xzw34Z8rsQn/4sCQ/tpSP/IvZLAthaPZB/hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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