SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d48b3b1ca5eb1263b8f106347ad32b6b8e9399b7d20c63f59da66443129e6d2' 
  AND token = 'SiYKz0dBiv2Nfo5RthwSZY3UjYmDugv9bHx+5ys/SV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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