SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02d0fc484ab6cd8bf052d6b6751415ade64033eab134603a1fd5e660d7acb337' 
  AND token = 'Pp/2TTh6SiOB6ONJrfQGwEpzrlvhCcjyPJ0unFpnmu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}