SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04f398c085e0884b40f3cf174875610d303e7279f96146b6e701d29c2a9ffb4b' 
  AND token = 'Gmdm+JFXSb4YH2wASPCvdNrU+/GRojbo1yVSOuSf5LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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