SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90b5b60c7885fa8e7beeb2146fea1f12ffc12e33270f6efedb1c3dddf928628b' 
  AND token = 'WrP59txzDkrEeyP2rkTFgx1LEgnvvyzSDWizPkoXgNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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