SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '808207e33b3e2c7a460dab8bca44df34555fa2e05d98b273b264c01aaafbe30f' 
  AND token = '3XLEWNZTeX1Muagc+joIgGDetSHaf+o02CnTbrycFUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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