SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b203e118ab6f18656aea482777cc75050c4fb79db98611a2b5c17b7db3b58c' 
  AND token = '8NVMmVq43qbsKDBjeD1fJ5CZsPOUFvkJhGhvK98FSpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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