SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd34085b1640aa903dd477e754cc3fc73836b43e926d65151af9903d5692bc618' 
  AND token = 'xqyvHs6k/XLZjJgNykbscg21O06cSlV3nNOjzRtSqWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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