SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e75a649ca210ba12febbd84f1321e768b0e05df2fe6f1732cafae4d369449c3e' 
  AND token = 'bJ1bN3GNeotjZR8NbWybSSh+RxMb3v7XZ66JgIo8zyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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