SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7f1ea0026777a2f34fd8c10a4aebb6d993145c12e2423a8bbd78e4749df7ab1' 
  AND token = 'lyWxkyp5GkxDbnPsVyd4mbM22xCG8nOOUTvV2RS69Gk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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