SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a79a9c4eb75a88f47aa241dd9d795d641cad5c135f97adedee17315da71f9165' 
  AND token = 'nz+POlBAGWgfyVLuADgnXfxbUbAEuftQSYsxizdfQGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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