SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71359858a9ff340d29170265c4e62776bc89c782ae7e6402b20c81156ff82037' 
  AND token = 'KpKS3Jq1CiHNpg8HpGHDuypl1sUVcRVf+2QLjuGJf5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}