SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0b22e924708faa8d7e38d9b32e5f7adc019d18331962e2f58820d4fe9241771' 
  AND token = 'O6Z/+qjRGf3Y2mECXeL9N5rZtRgC/3jRO0KwknpByhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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