SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b0f7d5261c312be834b3fce87d8469821e4c8e46f75918ec7a3a9cbea3da64' 
  AND token = 'GzdwaOWbpNyZiTeh9cls4cPiooaLOHbMVXcXAJYFCOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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