SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c27c832f231a3bbd563dbd5141e2acf77fbf0c7d5ec7000d4c6f2598ec5debb' 
  AND token = 'n3+kdodjSKnz0pDFXKkZaxaYmbhNllv9jTcelSBHxTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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