SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24b87263117da42f5b8cdf1ce13eb65ed4a48fa71e397af62b07f0a1822d27c3' 
  AND token = 'LJAzCV1Se1kkFBsiqpGdEg35sbhYjAwc2Ui/wyGrqYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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