SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8895ceb5911d58261335aac70521ecc1a62dec6c250af5506dea6233985631f6' 
  AND token = 'M7Zl9Ue8ULWy9KR3D8mcaeTutT8wo74njyllEXb0p7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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