SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de9bf7b10fd4f0489daee1909976caa06312e62cc5bb0bf5c30db87a3d8712ec' 
  AND token = 'BwRsMoWrPBUT/+moVUBrHwvQlnRy2hhJcylXuCSSuJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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