SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a893402b3bd9fabcd04b5259538345a7507d762699fce161d407110be8faaa85' 
  AND token = 'L0lj7GIfjvlzxuM8wBTegNz6lMC0sD/FXbM8Ks+dSQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}