SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ee30e90bc9c191da12a29c8bb4f2c03fcbdd1d0b588381150fa0718440f2e1' 
  AND token = 'sLSbgwbUSVkavBMksKjCfvd2NWtcz4Zvujyr6GSIODs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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