SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '171678e2edeba2abf72f3b5b15cc00f04b10597a33925885f68d19c0cfba9092' 
  AND token = 'zzXNOqzt6ivqpll9L5eDqfR6GBJiKViLNX/jn+8uQ1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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