SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4bed2c75fb5d65e245f7df0f027797192722ea55d2d496e02c63eb799fa3d3cc' 
  AND token = 'rkkRGiZcScIXfIO/nbnvEf/WnceeSo8ptIKdl8cPZMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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