SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04bc706975c7fd4e752f65e3f77976008225215933a0ce34cf0eca4d8fe9a3e2' 
  AND token = 'mLPbGGXDCP1I3kk90VScdLciqyAl1gY3PRpcG8VxB2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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