SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab90ee8fb12ed509f0e913285f81042c90e2bac73859210df8175482312b5e83' 
  AND token = 'ByenPimMC35TLrN1LSvQqtRJyOqKuFaBLaqo6rBmQbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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