SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6cee76f249d836ccedf1b03a73d576af11eb66e3591aba195382bd0b1da98fe' 
  AND token = '2BOcEcOyt7r9vY7EvjYVsHvi3foTrCKGMtU3no0Bmd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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