SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f056684111ddea9b1cd9998d32586244568b6388596f60c1980fa61294d332b' 
  AND token = 'YYFkNFxKMeULe/fEyo8myvEzoOfgqSN5jKubiTKena0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}