SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91dd6f093aa07ffce6b1721a60c7a3fb977578c6d96947ad587858139927c680' 
  AND token = 'Jy6UND/jSaJXqlv3cXxbXtljksb/2u025ObJWn05Dyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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