SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f57ecad4b1e1cf82caccc4aca601f2b52ca66378ab78f971fba27cb5085a5417' 
  AND token = 'fZW46YxFWgqvMOqKjRIDaxQYpPgE1kOYexwzdw3pPSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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