SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa8096704b4c9b798c5952bd81272dcc7a39d63d52522410b9307e2ea8c9766' 
  AND token = 'oXHjmOTjejnHWpiqHN4bOPTb+RXc0KCTtBRjuBEfrmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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