SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d2d96bac0cf5d4b747d514a4e32b6789d0fe21078ad4307159deb4d322739e' 
  AND token = 'ub/yI3q43UaN/9RFKSkLBzh/YgT/FjVsMfGLU1kxVbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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