SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd38308cda61b7206fd52e27dc6fc063d0af48476c11e4683cdb2388c0d451c02' 
  AND token = 'vPlgGEmC7Jp+hUhNa/eHw1hbEMfOr7wtQUvs058bQ58=' 
  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"
    }
  }
}