SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92fea39e024122279bc5275e83438c5e3cd5ad0e024152f898585ad270521b1f' 
  AND token = '2zC2NoMkpncFo6Wpqw6G3fjxRsGlN14eFNrTHdw/E6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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