SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0db0c5a8440eee7c93554e2f65f40cb6333d54d12e8dce1a75aedeabbbf5be6e' 
  AND token = 'pgwTvTybsRkY5IEwAOWRDOnCOuxuEVS2zCaiO3VjaRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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