SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e11515fc96440e2cdc094a9e3c742ef0fd2131cd2e6157525074efe62cdbb54' 
  AND token = '2+/p4U/OGATFDVzRHhUtni7sX7yJqmBtOq/hZ0FNLLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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