SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b041cf1182fcf56df5702d876dd5158ea9a7617f12e99b0254eccd7b0b21b10' 
  AND token = 'iXsUGbv4MWvf+uPB7rL3w+VNTMcclBaiQpk1iq1rkTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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