SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e7802cb78e941e0f7f9fc2d4f3b552fa1a36720ba38c88ac22362d7bbd50d19a' 
  AND token = 'zkwJLfdHi1ff6UfCTBEWMBMpFzyyHSvW7OXbMp+ZhrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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