SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0537eeb9ecabfad92050c610d6dc771fe383ac03a8c165ba6296ac590c58cfe0' 
  AND token = '19dAWpJibTGGCC0uDrN9ZvjdZ5wxoqhsvmDCz6gRNcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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