SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffc9e7bfd412641f617bb311c275b5afefd72374d8b2355b35a626770cd2404b' 
  AND token = 'bqLZtOs7XYUix9DbPmZlRU1CUfIWbWbyt0VFLfjwXYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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