SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28ee968b39a1e89d2a5a2c94643dcf26821d89a84fdfd5913aa8f2c2931a0fb5' 
  AND token = 'hCVLLRZL7DnNN42j6AxtXSjN7JOAghCPn4W0zvXRQxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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