SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69c6fa365adf2447d57108c150e60cd1ac94254e824b655dc2ac4ae6d377e0da' 
  AND token = 'tFMy21AhLQw7wvV622LWUVhFgMjkUScPpCUiHhrimNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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