SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d30f69aaab74e5db84616a841c1c3af89ff1ce6f3702ec929f3c9ba34ed647' 
  AND token = 'NHUzhmPA2sxC7Jjr+QwyO4C6uLSovgW1GYFCR2Ypn0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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