SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5262ebb499b7d024e46bedf7910f6d7966ee3eef8483494e0232663ea745bdc4' 
  AND token = 'jKnvPo4WrK6P9r4J0LFWj2lGIXx8CDBaa9RL6y0fMeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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