SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d795b32f22d7532060fac1f9b5a401f2f67b958f5bcb2c95a1e162e03876d9' 
  AND token = 'WiWPqHXvvZBGHKwJsoTb36h+7fUdp9RgBbPrPNckJxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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