SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d36641041a6c045de75a7e8031e5f65793eb09402b1cea91361384519014aee' 
  AND token = 'jDa5ilrZlzGbSdbJcVcYQ1MEMmvCC/lFFfc/uXpB9Tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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