SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52be9d2e92a352476fe9c50c1a98627e9b0e0d674a4789b23e6dbbaa1e06a6d7' 
  AND token = 'UYqVXvff7LZxRNOwqrO5a/FwBjHtcL/CCGCK76NRk+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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