SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0968cf5ddf23b3a91e437ea6fe31d2bf30a3fbed3af7929fac2e9d3113d8fbe' 
  AND token = 'QqPJwpUvYyuO3g2FoKfpqT1ATDxzi8XZWlQHPN0p5WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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