SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ae38c2f031c16b81d9f10c3eacf2fe647a4feb909990fb4f8523382262f253b' 
  AND token = '7uvF7NOjdcKvJLywT7HT261VeNd1v7yYyGNEEOlSKzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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