SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5957a5bcd7209313e3cca698e0992401b9de3d4a6a98912dfbbb3557059da2' 
  AND token = 'lghZt4XOuIXaGXbxF75QCtNp+FFRaQ6bcEbHSifA3FM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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