SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e515e0b31625b2f764a3f476c1a456650de4dea91908f410b59feab8738150' 
  AND token = 'wQQE/izIqbcLRwvfINsEWaTzSYBMH9J49FFgNf3wFfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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