SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a319a4235dce879010f3bc06be24a063100f2957a12253b1931db47bbddbed48' 
  AND token = 'aFT7/ENawZA81GghohW/23a9tKhkNPjXYMRc2wiY5mQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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