SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f613a93cfcb4b465182f86ecab98076461bdee81abd818b17743b2c25af3cc59' 
  AND token = 'Qc2SEkw/gJqM+KBVLOXg2/BVRODDU756ZnDUb4dvYG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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