SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '645f3af39b5205655eeec372a4fa5720eb03a4f57e0007bda683c6cee7c30eec' 
  AND token = 'HMmqTLgHnADb0/TT+FmdiafopgpEQuBsChZwCvpw+u0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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