SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af6ebaa372c10069d9901456af8dea46a0913508ef720a159fb5261821910d98' 
  AND token = 'wagNtKqTZE8UR+7LxkX85XWKtWGpkWBlvaKw7wpC9uE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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