SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d214b20675946af015269dbc1658c739c9c1074b4d94199d8ad4f3ca73e513' 
  AND token = 'bSKQX//5/hUn4E/gVCjJMJNh5o75b57dXKGNrfmyqOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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