SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a730fda65934117c01f16929ff538c996c7c31b65fe3380f884f41daec305c9b' 
  AND token = 'MZWg20CKwkxvSxI/oJG7+o+0nvBvxgzBo/nh27490rA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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