SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f3c5e246cffeb0e0482c6a83dd404ddb57a6570b56489e629661aebe17e1f3' 
  AND token = 'FHBtlkhct6PdJfllI1XDw74zn7YT4p4yU+8iFiwHc2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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