SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '703a93126ed633da649a6dba08c4758f15b288d7e55f75f357158dcf8cb34c22' 
  AND token = 'ihqW5pDwJDA/3lDRQ7Hf/nrCYn87i+kqygCK60v8OhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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