SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '261e1d398cc49b4a03dfe686f1a1662226f510e97a030281f03cf9060612df3a' 
  AND token = 'rdKv60wfVZL1sramtalU6LD2wPWyPhiBL8CEfKiRGxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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