SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3965c2d8a21beaedfb39101ace496626b46e422cd92f783d40b318c22325ab' 
  AND token = 'KKWpUXuFV2UtMMbBcV+t5jevDLgjef4NePqCyRfZ1uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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