SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb5f9185af327faad37836ea5f8dcdefca4666a373483f1101e195e99ac47f04' 
  AND token = 'Q15yiIhOJTFAPuTAB/zwPQh6VdXFIVcTyr9DkmnMFsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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