SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84b6498c1c82207ec8ba382d821965142a35083bb7475e0f30fe7782538ee11' 
  AND token = 'cY55phtyvWKoNAXFwk7S1dU8mkhjRa9+94sJFI5DcmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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