SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ee4fc50a132d7e81f4b0eb38dc796edce7f8246aaf8989b96d08ebc0574cf87' 
  AND token = 'uCd9bF8jcDYdAoPttaIYVwSL2qVyCncbLCPH6lwHgsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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