SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df98b441149e7077d124eb50460555e90b3140a05eef72e11baf77a538659f0d' 
  AND token = 'ratWBBR+biANEBFgyI8zC5l7amYZpK5iyKeUV8vJRVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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