SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2e9940ea29841f5c88d63199c65f8a2d173d736c29c279ea37926313e1794b09' 
  AND token = 'ztqr3WWwWjatL/UBrlgbRteAPlzHzRptCKdhmrzkRG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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