SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4470043282841e399e2991812f99665ecc14d2ce3fcc966913ac5746cc02b2ad' 
  AND token = 'Wu7vipMTdXj5es73KtAbFHypnWFUOgVppVjDjTa7MSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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