SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84caeddc645c8651aadd46b9a5f640d0814278781e1fb6c413a302ed54a791f8' 
  AND token = 'DllOrWwBQgr14P/uBRT1U9hAWwqx7iZTDIOmi1kN/cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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