SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278873b9ee5ef02edbe751097305ceb9e3ca5f5e469609d41064f68da4402ae1' 
  AND token = 'Yr7ogszjxsGZqBY/Gehi+zi5+VKw/C/L+DHYVZFwVso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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