SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b3338977b65f5df56a78a4868ed9d1cdc4bd1e291fff80662a7ffd43596a4bd' 
  AND token = '8z4/W4tEANU8zhuHZF5EwQgfI7qlRwrraVms04YRggg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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