SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8d3acbbc3554e11a2116cc79a38d977593fa868db067b0779c613050d65ac80' 
  AND token = 'CHCsAYHmrKOdcIrqnzxd2bIYH6T6FMOswlFRBTjvFng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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