SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51837664b116f88f9b7ed430f639bb76a07a75206cbfaa1f33a4bb6d8d322e00' 
  AND token = 'H7PIw+MKWd+vjiuhvN71/8VroLLQ/UVwALX3GrrZw9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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