SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76c3abb3186b7b56f1cadf5cc96744259b3af062045459414da85a9ca867a924' 
  AND token = 'XDRJxrLCy+VIyY90vbPY/zbNPGFnBfL7AubldYrwu5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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