SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea6a0aee1c6f1b6b97f6f62ebae8e755997f2a0546b5ad5a0c977619b6d0f9c' 
  AND token = '8Wng3b9ryOzkiGjZRqf0merThCFik8U/V1YMwwO/JIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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