SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fdc76092441481a7c5f6ad542a9e8ddf837bd863f338286fb6d9b80cb321192' 
  AND token = '/KM8uCpUiF9HkMJTgBMUQfjTZrGG1ggpROXHIhfQ/xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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