SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab7aeb4474b9185bcf84a616f3eb437189bfcadfde615b709a023016f19f79f8' 
  AND token = '8f9oNAWXKJzRdnX3x9cAfEtbn5c2giqJ6xcj4ruCffw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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