SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bb043907c6fc2822f8c22f0a209eb9e45974be7054e2e2ddb9043b6ce1b60e3' 
  AND token = '0E/gmc1No4QgNstqp6EOJwtAvFhfvmT+hOs/XfDD8dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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