SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b418223a0175b070fbf2834c6b37ad2e817768f52d499466efd51c6136c41a0' 
  AND token = '0TlThplCqlezwOgKJ7Oo9bBzTEu6/vTDgjIUwKANK7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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