SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbf15ff69dd002a855d1b1e3303e36ef70f37e53411eefe2faef6e34e9fe0ef9' 
  AND token = 'nm8t5pqY9l9OQvUGiK3yQ4ERkhBbM0FyKS2EtP/1VFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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