SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc688cd278b95be2746931afbb0504c1781f3b5bb002d23eb9119ff618176806' 
  AND token = 'CbSCop1SyRIJUbqjgkcPeee9WFM14dvFg54Yx3FnUpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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