SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0eaa68ac0396f0b6870806907a89f66bb8888e357dffb102bdd62b7d8647dd4' 
  AND token = 'WOnrCr3hRNrxU0cUqjoZHyiurbWgu/vq6mHquZ70Zak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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