SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd74241325004acdee03ee95bd72af41136db720052c3c444231bfbb67c7a7ba3' 
  AND token = 'DbEmUOniWc8pt7p18qjqrUF+ejHE/3h229nyo6wP1gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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