SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6731bf257833b66e3394c2792149f8dbb48ff5ef5f75ae1e83db77ddf2539fec' 
  AND token = 'ZU3XZx0s9DHKR+tiNhsctZhayoABApqYR1bxAqFGGV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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