SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9570cb130de7db2602fcc97edfe31fb749d196085e401dfa668ab403da01d41' 
  AND token = 'I0AHpdjqVWFhjNmAI1c3BALvBvNONqUYT/gYYzhMhuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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