SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf772919d5c6d3f0b462c4f046514995cc24eb99849349668d2181751f3fa78b' 
  AND token = '7FsElHBl+uh7uChjk8DcG4bFXV4ryggwZS27aLSL1EU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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