SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fbf77e255bc4b547f2b8c4a8ec3d6f4b66915f1a40035befa2a3c91e19091f3' 
  AND token = '8MLgNTtCodc9IrLJT3nDvKwy0IS6nJVDVkxHYkE6Kyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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