SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '15103e916252443d6f33ee0f57b0f1e5019d59c5ce4ad5abb9d5f9d6444029b8' 
  AND token = 'KFULfQnCrphR8iQAKdWD/uXBXM+JoYfuB5kM1lEajCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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