SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '843382a5e1a8324fd9ffdb5efcdd5ffd50f1542dca1ae8515c14ed5174f0cc50' 
  AND token = '58WWTBDKoPCsbDj/h/MnwHa1L0agGg4kqDbklv6WOV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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